How much heat before barrel fails?

[ARCHIVED THREAD] - How much heat before barrel fails?

Posted: 12/12/2001 11:48:54 AM EDT

I'd like to replace the CAR barrel on my Eagle with a chrome lined M-4 setup. I figure I may as well use up the barrel first before I remove it. So how much rapid/bump firing would I have to do in order to ruin it. Will I endanger myself by doing this? How will I know when it's time to replace it?

Posted: 12/12/2001 1:18:16 PM EDT

[#1]

Before you ruin the barrel you will get to the cookoff point. That is when the chamber is hot enough to detonate the round. Usual result is a runaway (VERY Dangerous).

You can tell when its time to replace the barrel when groups get really bad or it fails one of the tests in the -23&P for straightness, throat erosion (good luck finding the gauge), or headspace.

Posted: 12/12/2001 1:23:22 PM EDT

[#2]

i was tought that one round of auto fire = 10-15 degrees. after 2-30 rounds on auto pretty much melts the rifiling out.(persionaly i wouldnt do it though)

Posted: 12/12/2001 1:55:54 PM EDT

[#3]

I called Quality parts Corp/Bushmaster up one day and I spoke with Tom Barr, and he said that on semi-auto you can't pull the trigger fast enough to damage the barrel.

Posted: 12/12/2001 3:32:44 PM EDT

[#4]

Quoted:
I'd like to replace the CAR barrel on my Eagle with a chrome lined M-4 setup. I figure I may as well use up the barrel first before I remove it. So how much rapid/bump firing would I have to do in order to ruin it. Will I endanger myself by doing this? How will I know when it's time to replace it?

I have shot 4 30 rnd. mags and 4 20 rnd. mags consecutivly as fast as I could. Thats 200 rounds. Nothing happened but a super red gas tube and a tired trigger finger. You cant screw up your rifle uness you wack it against a tree and still it takes a couple of good whacks.
GG

Posted: 12/12/2001 5:40:54 PM EDT

[#5]

Maybe I am being Captain Obvious here, but why destroy the barrel? Why not just take it off and sell it?

Posted: 12/12/2001 5:53:53 PM EDT

[#6]

The gas tube would probable go out before the barrel. Since I have seen machine guns barrels red-white hot and they still had rifling after they cooled down, I think the rapid fire will just reduce the service life, but not destroy the barrel

Posted: 12/12/2001 6:20:56 PM EDT

[#7]

Quoted:
Maybe I am being Captain Obvious here, but why destroy the barrel? Why not just take it off and sell it?

What he said. Hell, instead of selling it put it on a beat up old upper (you can find them pretty cheap) and use it for a dedicated .22 upper. But then of course you got to get the .22 conversion.

Things could be worse!

Posted: 12/12/2001 8:47:55 PM EDT

[#8]

Thanks everyone. I'm not one for selling things if it's still of any use to me and besides, I like destroying things. I figure if I use it up or sell it, I'm in the same position. I may as well get my money's worth out of it and have some fun doing it! Maybe I'll stick a hotdog in the lower handguard and see if I can cook it!

Posted: 12/13/2001 4:43:53 AM EDT

[#9]

If you want to destroy the barrel by shooting, you need to put the alum dovetail rails on it, then the panels on top so the heat won't escape, in no time you have fried the barrel, amongst other things.
Good shootin, Jack

Posted: 12/13/2001 4:59:36 AM EDT

[#10]

Personally I think your "I like destroying things" comment says alot about ya, however there was a thread here the other day about a 10,000 round test on a new Colt H-Bar, the barrel was finished (due to constant shooting) after around 8000 rounds. It didn't fail however, they finished the 10,000 round test, so you'll have to go quite a few thousands over them to get a failure.

Of course you'll spend a few bucks getting the ammo to "destroy" your barrel.

Mike

PS - Looking forward to seeing ya soon at the Darwin Awards.

Posted: 12/13/2001 6:48:27 AM EDT

[#11]

STLRN is right; thegas tube will fail before you do serious damage to the barrel, the gun, or yourself. I've done a lot of shooting in full auto and in my experience, depending on manufacturer and quality, the gas tube will fail somewhere between 100-200rds (shot full auto, with either beta-C's or with 30rd mags with no more than a 2-5 second break between mags to get a fresh mag in there). Some gas tubes will even fail before 100rds. Once you let it cool off, you'll see there is still plenty of good rifling in there, but once the gas tube is fried, the gun will stop dead.

Posted: 12/13/2001 10:09:14 AM EDT

[#12]

My vote would be to use a hack saw on it. In addition to destroying the barrel you get some good aerobic exercise.

Posted: 12/13/2001 10:40:13 AM EDT

[#13]

Quoted:
i was tought that one round of auto fire = 10-15 degrees. after 2-30 rounds on auto pretty much melts the rifiling out.(persionaly i wouldnt do it though)

No offense brother, but who the heck taught you that? It takes 5 full 30 round magazines at full auto just to get to the point of a *possible* cookoff. Damage the rifleing? Not hardly.

Posted: 12/13/2001 10:50:05 AM EDT

[#14]

Yeah, if a couple of magazines of full auto melts the rifling, maybe the Military ought to consider better rifles.

Posted: 12/13/2001 1:00:14 PM EDT

[#15]

I don't have experience doing this but I do remember reading in a post where someone had tried it. I recall reading that the gas tube melted before there was any problem with the barrel. Sorry, no info about how many rounds and how fast.

Posted: 12/13/2001 5:30:53 PM EDT

[#16]

Quoted:
STLRN is right; thegas tube will fail before you do serious damage to the barrel, the gun, or yourself. I've done a lot of shooting in full auto and in my experience, depending on manufacturer and quality, the gas tube will fail somewhere between 100-200rds (shot full auto, with either beta-C's or with 30rd mags with no more than a 2-5 second break between mags to get a fresh mag in there). Some gas tubes will even fail before 100rds. Once you let it cool off, you'll see there is still plenty of good rifling in there, but once the gas tube is fried, the gun will stop dead.

Its going to take more than that.
GG

Posted: 12/13/2001 10:47:27 PM EDT

[#17]

Originally Posted By Gun Guru:
Quoted:
STLRN is right; thegas tube will fail before you do serious damage to the barrel, the gun, or yourself. I've done a lot of shooting in full auto and in my experience, depending on manufacturer and quality, the gas tube will fail somewhere between 100-200rds (shot full auto, with either beta-C's or with 30rd mags with no more than a 2-5 second break between mags to get a fresh mag in there). Some gas tubes will even fail before 100rds. Once you let it cool off, you'll see there is still plenty of good rifling in there, but once the gas tube is fried, the gun will stop dead.

Its going to take more than that.
GG

Not in my experience. I've seen gas tubes from lesser quality manufacturers fail at about 70rds, full auto from a beta-C. The most I've seen is about 180rds fired full auto from back to back betas. They may occasionally go farther but beyond 2 betas, in full auto dump all the way, is more the exception than the rule. That is, of course, assuming a standard gas tube; if you use a LMG upper with heavy gas tube or a pigtail or cryo treated tube, you may get a little more trigger time before failure.

Posted: 12/14/2001 8:05:05 AM EDT

[#18]

Quoted:
The most I've seen is about 180rds fired full auto from back to back betas. They may occasionally go farther but beyond 2 betas, in full auto dump all the way, is more the exception than the rule. That is, of course, assuming a standard gas tube; if you use a LMG upper with heavy gas tube or a pigtail or cryo treated tube, you may get a little more trigger time before failure.

Where are you getting your gas tubes from?

SF uses lots of full auto (hence the short barrel life 4-5K rounds) but doesn't burn up gas tubes like you are.

Posted: 12/14/2001 9:00:34 AM EDT

[#19]

Quoted:
SF uses lots of full auto (hence the short barrel life 4-5K rounds) but doesn't burn up gas tubes like you are.

No one including SF fires 100 round bursts

Posted: 12/14/2001 9:12:07 AM EDT

[#20]

Between me and several guys I shoot with, we've tried a number of different manufacturers - Colt, Bushmaster, M&A, etc. Obviously Colt & BM were the best. SF does use a lot of full auto, but its in short controlled bursts; they're not dumping back to back betas with the hammer down all the way. Its just a problem inherent to the design - that thin walled gas tube has much less mass than the barrel so it'll heat up faster. It'll work great in semi or short bursts, but its not designed for prolonged full auto fire. Thats what the M249 is for.

Posted: 12/14/2001 9:35:32 AM EDT

[#21]

Quoted:
No one including SF fires 100 round bursts

True enough. I didn't anticipate he would load a magazine and just empty it with one trigger pull. Gotta be lots of fun <G>!

I figured he was emptying it in typical 3-5 round bursts.

[ARCHIVED THREAD] - How much heat before barrel fails?

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